Longitudinal characteristics of spread F backscatter plumes observed with the EAR and Sanya VHF radar in Southeast Asia
Longitudinal characteristics of spread F backscatter plumes observed with the EAR and Sanya VHF radar in Southeast Asia
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EAR和三亚VHF雷达在东南亚观测到的扩散F后向散射羽流的纵向特征
DOI：
10.1002/jgra.50581
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Libo Liu
中科院分区：
文献类型：
--
作者：
Li Guozhu;Baiqi Ning;M. A. Abdu;Yuchi Otsuka;T. Yokoyama;M. Yamamoto;Libo Liu
赤道等离子体不规则羽流的发展可以很好地记录在磁赤道上和磁赤道外操作的可操纵反向散射雷达，因为垂直延伸的羽流结构是磁南北对齐的大尺度结构的示踪剂。根据2012年3月期间的观测，使用东南亚的两个低纬度可操纵后向散射雷达，赤道大气雷达（EAR）（0.2°S，100.3°E;倾角纬度10.4°S）和三亚VHF雷达（18.4°N，109.6°E;倾角lat 12.8°N），同时研究了经度上相距约1000 km的两个地点的后向散射烟流特征。波束控制测量揭示了两个雷达站点上频繁出现的多羽流，这里分析了其中的两种情况。2012年3月30日的观测显示，在雷达扫描区域内形成了羽流结构，随后，其他羽流结构从两个台站的雷达波束以西漂移过来。对等离子体羽流起始位置的追踪分析揭示了空间上分离良好的后向散射羽流，最大东西波长约为1000 km，周期性地产生于85°E和110°E之间的赤道。三亚甚高频雷达观测到的日落后后后向散射羽流，是由西经附近的日落羽流通过引起的。最有趣的是，2012年3月21日晚的雷达测量显示，在雷达扫描区域连续发展出多个羽流结构，东西间隔约50 km，但三亚上空没有日落等离子体羽流。共点电离图测量结果表明，扩展的雷暴主要发生在三亚的底侧F区，而当晚在两个台站都观测到了电离图中的卫星迹线，这表明了大尺度的波浪结构。对雷达后向散射羽流特征纵向差异的可能原因进行了讨论。
The development of equatorial plasma irregularity plumes can be well recorded by steerable backscatter radars operated at and off the magnetic equator due to the fact that the vertically extended plume structures are tracers of magnetically north‐south aligned larger scale structures. From observations during March 2012, using two low latitude steerable backscatter radars in Southeast Asia, the Equatorial Atmosphere Radar (EAR) (0.2°S, 100.3°E; dip lat 10.4°S) and the Sanya VHF radar (18.4°N, 109.6°E; dip lat 12.8°N), the characteristics of backscatter plumes over the two sites separated in longitude by ~1000 km were simultaneously investigated. The beam steering measurements reveal frequent occurrences of multiple plumes over both radar sites, of which two cases are analyzed here. The observations on 30 March 2012 show plume structures initiated within the radar scanned area, followed by others drifting from the west of the radar beam over both stations. A tracing analysis on the onset locations of plasma plumes reveals spatially well‐separated backscatter plumes, with a maximum east‐west wavelength of about 1000 km, periodically generated in longitudes between 85°E and 110°E. The postsunset backscatter plumes seen by the Sanya VHF radar are found to be due to the passage of sunset plumes initiated around the longitude of EAR. Most interestingly, the EAR measurements on the night of 21 March 2012 show multiple plume structures that developed successively in the radar scanned area with east‐west separation of ~50 km, with however no sunset plasma plume over Sanya. Colocated ionogram measurements show that spreadFirregularities occurred mainly in the bottomsideFregion at Sanya, whereas satellite traces in ionograms that are indications of large‐scale wave structures were observed on that night at both stations. Possible causes for the longitudinal difference in the characteristics of radar backscatter plumes are discussed.